Gaskets are often used as a seal between mating metal surfaces. Common applications involve the placement of a gasket between a cylinder block and a fluid pan or a valve cover of an internal combustion engine. Such a gasket provides a seal that retains engine fluids vital for engine operation and prevents them from either escaping into the engine compartment of a vehicle or contaminating other vehicle components.
In an engine, gaskets are typically installed by placing a gasket between a cylinder block and a mating component and aligning bolt apertures formed in the gasket with corresponding apertures formed in the cylinder block and the mating component. Generally, a threaded fastener passes through the mating component and gasket and engages a corresponding threaded aperture formed in the cylinder block. Some maneuvering of the mating component and gasket relative to the cylinder block may be required to align the apertures therein with the corresponding threaded apertures of the cylinder block before fasteners can be inserted. However, during the assembly process, the gasket may slip from its desired position or drop off the end of the inserted fastener before it can be fixed in place.
Attempts have been made to retain a gasket against a mating component prior to and during assembly by providing separate clips for attaching the gasket to a mating component. Using such clips, a gasket is placed adjacent to the mating component, and the separate clip is attached to the mating component such that the gasket is secured in place between the clip and the mating component. The separate clips typically include one end for contacting the gasket about an outer periphery thereof while a second end is attached to an outer periphery of a mating component or to an outer periphery of a connecting portion between mating components. Use of such separate clips does not eliminate the problems involved in the assembly process whereby a gasket may slip from its desired position. The clip attached to an outer periphery of the mating component may be jostled or become otherwise dislodged by contacting adjacent parts and potentially falling into the fluid pan or engine bore causing later interference with engine operation. Further, separate clips may become dislodged during sub-assembly, handling, and shipping of mating components, allowing the gasket to slip or drop. As a result, the gasket may become offset or mis-aligned from the holes to be sealed before assembly, again requiring some realignment of the mating component and gasket to achieve a tight seal. Assembly of a gasket to the mating component using separate clips is also a complex operation, requiring multiple parts and means to hold the gasket adjacent the mating flange while the clips are attached.
Another attempt to retain a gasket against a mating component prior to and during assembly involves the use of an adhesive. The adhesive is applied to the gasket prior to its alignment with the apertures of a mating component. The use of adhesives has a number of disadvantages. For example, the gasket could become accidentally misaligned or displaced before the adhesive has set, making it difficult to return the gasket to its proper alignment. Moreover, adhesives may detrimentally impact the material load bearing properties of the gasket while in operation, thereby adversely effecting the seal integrity. Adhesives lower the ability of the gasket to carry high loads because the adhesive reduces surface friction between the gasket and the mating component generally cause the gasket to slip from its sealing position under the application of high loads placed on the gasket.
Another commonly used way to retain a gasket against its mating component prior to and during assembly employs fasteners installed through the bolt apertures of the mating component and the corresponding bolt apertures of the gasket. These fasteners must match the size and thread of the bolt apertures, requiring an array of fastener sizes to accommodate differently sized apertures. Installation of the fasteners also complicates manufacturing by first requiring installation of the fasteners as a prerequisite assembly step followed by fastener removal prior to insertion of the actual bolts. More importantly, the fasteners increase the assembly process complexity. The fasteners, although retaining the position of the gasket on the mating component, often interfere with the maneuverability of the mating component and gasket when brought into alignment for installation to a component such as a cylinder block.